int/linux: add/use Getwd

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

internal/linux/eintr.go

@@ -16,3 +16,13 @@ func retryOnEINTR(fn func() error) error {
 		}
 	}
 }
+
+// retryOnEINTR2 is like retryOnEINTR, but it returns 2 values.
+func retryOnEINTR2[T any](fn func() (T, error)) (T, error) {
+	for {
+		val, err := fn()
+		if !errors.Is(err, unix.EINTR) {
+			return val, err
+		}
+	}
+}

internal/linux/linux.go

@@ -6,6 +6,12 @@ import (
 	"golang.org/x/sys/unix"
 )
 
+// Getwd wraps [unix.Getwd].
+func Getwd() (wd string, err error) {
+	wd, err = retryOnEINTR2(unix.Getwd)
+	return wd, os.NewSyscallError("getwd", err)
+}
+
 // Sendmsg wraps [unix.Sendmsg].
 func Sendmsg(fd int, p, oob []byte, to unix.Sockaddr, flags int) error {
 	err := retryOnEINTR(func() error {